Pascal’s recent thoughts on 3D (#1181 on 3D and pop) are a tough act to follow! As announced, here is a second instalment with a slight change of subject—or at least of approach. In this post I’ll write in my own allegedly “academic” way, seeking to separate out and analyze a few factors, and hope that our two different approaches will both be useful. Our images may be different, but I believe our ideas are in harmony.
How can we see distance in the flat surface of a photograph? Let’s take a step back and ask: how can we see distance with our eyes? After all, our retinas are flat surfaces (any bumps would occasion a visit to the ophthalmologist), yet most of us see a wonderfully 3-D world. Our complex visual apparatus has a number of tricks to get from there to here: it utilizes different kinds of receptors, parallax, focus, eyeball saccades, proprioceptive data, and much more. In addition, the brain has some amazing algorithms to sort through the huge amount of data. In fact, seeing distance is greatly over-determined—as well it might be considering its importance. After all, it can be a matter of life and death to accurately determine the distance of a predator. We trust our eyes implicitly, although maybe we shouldn’t be overly confident that visual appearance is reality.
Photographs are two-dimensional like retinas, yet they usually portray a three-dimensional world (abstractions excepted). How is this possible? Well, it’s easier in stereoscopy, where two different lenses provide sufficient parallax to fool our eyes when properly viewed. It’s also easier in video: where time is added there is movement, either in the scene or by the camera (including change of focus), again fooling the eye.
But how can we suggest distance or depth in a still photograph? Surprisingly, there are quite a few cues, most of which can work together to give a strong and natural impression of a third dimension. I’ll present a list which complements Pascal’s. Though I have tried to be comprehensive, my list is surely incomplete, and you are welcome to add more items, or perhaps to slice the cheese differently.
(i) It’s hard to find images that illustrate only one of the cues, so my examples are ones in which the feature in question is prominent, not exclusive.
(ii) These different cues are for analytical purposes only. Photographers in the field won’t consult them, but they may upon reflection realize they’ve been using some of them all along, and they can think about looking for others next time.
(iii) Consider my comments as tentative generalizations (a phrase that many people don’t seem to realize is redundant), open to counter-examples but still providing useful summaries.
(iv) All my images were taken with one camera and one lens, a Sony A7III with a walkabout 24-105 mm zoom, in contrast to Pascal’s arsenal.
More distant objects tend to be less intense and on the blue-violet end of the spectrum. Sometimes the subject of interest is in the distance, like sunrises and sunsets, or mountains far away lit by slanting sunlight, and then we will try to make them as light and clear as we can. But mostly we are interested in something closer, and color is sometimes useful for indicating this.
Here the distant mountains fade into blue, obviously farther than colorful foliage nearby. This is a view from the Blue Ridge Parkway looking west, late afternoon in mid-November.
Overlap or occlusion
Nearer things block out further things on the same line of sight. This is fundamental to the world we construct from visual data.
Forests are paradigm examples of occlusion, and trees that block out others are clearly nearer. This is the local forest in mid-February, with trees advancing down the hillside. The distant hills are also bluer as well as being occluded by the trees.
Larger things seem nearer than smaller ones.
These tree trunks, taken in early March, rely on occlusion, texture and focus as well as size, but size does duty for nearness as well (I think the diameter of the two trees is actually about the same).
There are three kinds of perspective at play in photographs (actually four, if you count other kinds of leading lines), and they may be variously combined.
Aerial or atmospheric perspective: Distant objects are normally less distinct, blurred by haze. This blurring is literally in the air, and not in the camera like bokeh.
This image of House Mountain was taken from North Mountain last December; the Blue Ridge Mountains in the background are blurred and less distinct. Color and occlusion help as well.
Renaissance painters famously exploited this form of perspective, where straight lines converge at the horizon, to give their images (the illusion of) depth.
This footbridge was installed over the South River late last year. The girders are maybe a little too obvious in their convergence, but they leave no doubt about what is near and what is far.
Sometimes the lines aren’t straight Euclidean ones but curved; this can be obtained with fisheye lenses or extreme panoramas. Some dislike the effect, but it can be interesting, and certainly conveys depth.
This Rockbridge County road in January does indeed curve around before me, but the effect is enhanced by the panorama. The mountains in the background covey depth as well, since they are familiar objects that are less distinct than the field, although they are snowy white, not distant blue.
These can be straight or curved lines, as before, but they can also zigzag their way into the distance. They lead the eye (or the eye perceives them as leading) into the distance.
This street runs in front of our cottage, but it doesn’t run straight into the distance, it curves. I desaturated the image because then you won’t focus on the old dirty snow. There are quite a few distance markers in this image.
Shades and shadows
Lighter tones usually, though not invariably, suggests nearer subjects, darker tones more distant ones. Sunrises and sunsets are prime exceptions.
This is not a particularly good image, but it illustrates the point: the crocuses are lighter than the distant house.
The hills are a mile or so distant, but there’s a lot going on in the sky, which is even more distant: clouds, contrails and the afterglow of sunset.
Elevation above the horizon suggests distance, while closer things are usually beneath the horizon.
These hills (upgraded to mountains in the local lexicon) undulate into the distance, and the higher they are placed in the photograph the more distant they are.
This photograph (of a photographer taking a photograph) of the California coast at twilight has several distance cues: the prominent leading line of course, the color gradient, but also the height of the islands in the photograph. In the dim light, I had to bump the ISO to 25,600; it’s a wonder there was a usable image at all.
More finely detailed objects appear nearer than more distant ones. After all, we’re accustomed to the acuity of our vision falling off with distance.
This nearby forest path has a leading line and occlusion of tree trunks, but also the nearer trunks are more finely detailed (especially because they are more in focus).
Objects we can readily identify may appear closer than ones that are strange to us.
These vultures stretching their wings to dry after a snowstorm are familiar enough that we can place their distance reasonably well, and they may even appear closer than the fence, which they are not.
Connectedly, familiar objects can help us size up unfamiliar objects and hence place them at the proper distance.
We (think we) know the size of cows, though they are really quite large animals, and their relative size in this image is one of many distance cues. Others include the leading line of the trail, the dark hills, and the sky, a form of linear perspective.
I saved this one for last, because it is over-hyped by fast-lens fanboys and doesn’t always convey distance. There are degrees of defocus, of course, and while a touch of bokeh can suggest depth, extreme bokeh just yields a fuzzy background, good for isolating portraits perhaps but not very helpful for depth. Bokeh works best with other cues such as shades, textures and occlusion.
These three trees are in differing focus, with more detailed texture in the closest trunk. The curved twig is a leading line from tree #1 to tree #2.
I close with a few “flat” images for contrast. They illustrate the subject by their relative paucity of distance cues.
How far away is this rock face? Actually it’s only about 10 feet distant, but it could well have been further. I wanted a drab palette, as well-focused as I could manage under the conditions (24 mm, f/10). The trees do indicate a receding hill, but overall it still seems quite flat to me.
How far away are these (mostly sycamore) trees? Actually they are about a quarter mile distant, across an unseen pasture and river. That’s a four-lane highway running through the trees. Everything is flattened in telephoto land.
I deliberately inverted this rock face image to remove some light and dark distance cues, with only the vines superimposed on the cliff providing a smidgeon of depth. It’s verging on an abstraction.
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Hi Lad – well you and Pascal seem to be writing a book on “How to Take a Better Photograph”!
I adore this one – “The hills are a mile or so distant, but there’s a lot going on in the sky, which is even more distant: clouds, contrails and the afterglow of sunset.”
Thanks Pete. Though I’m sure you have more to say. 🙂
“Snap” – I am, too (sure!) (I was just standing aside for a change, to see what everyone else had to say).
thank you for this most interesting post.
The variety of your shots to illustrate the various styles you wish to present is remarkable.
And a lesson to some us (including me). One body, one lens (albeit zoom).
But most importantly, the quality of your pictures leaves nothing to be desired, as always.
Finally, yet again I’ve learnt something
Thank you Lad, thank you Pascal J. too. Cheers.
Thank you so much, Pascal; I do appreciate your kind words. I think all of us should be life-long learners.
Nicely done – as usual – Lad! You’ve organized the wonderfully informative post into clear and well-defined sections AND you’ve given us your beautiful images for examples. Loved the image of the vultures in the tree, among others. Kudos!
Thanks Nancee, on both scores. I’m trying to combine my philosophical bent (analysis especially) and my photographic one (whatever presents itself).
We have two types of vultures, turkey vultures and black vultures; I think these are the former, but I’m not at all sure. I should add that they like to roost in these dead trees on the outskirts of the retirement community where I live. Hmm.
OK – back to work.
1 – “All my images were taken with one camera and one lens”. Great idea. That’s the best way to learn! I have to say that – one, because it IS how I learned (I think I’m right in saying I’ve had six cameras like that, over the years – most of them back at the beginning) – and two, because I’m doing it all over again with my first excursion into Nikon’s Z range, with a single zoom lens. Of course doing it with a single “zoom” isn’t quite the same thing, because it covers everything from wide angle to (at least) medium telephoto, but let’s get back to you.
2 – Colour. Digital is fascinating. If you go beyond merely taking the shots, as most people do these days – what is it, 99% or more of all the photos taken each year now, are taken on cellphones and never see “post processing” or “printing” or any of those old-fashioned ideas? If you get beyond that, and you’re on digital and not still using film, then one thing you CAN do – quite easily – is analyse. You started with colour,. so let’s look at it. What happens when you strip the colours, and convert the shot to black & white? Do the “shades of grey” in your image still reflect the composition you had when the image was still in colour? This is just one example of many ways you can enhance you photography these days, using digital and doing your own post processing.
That particular example is interesting – no matter how much you liked the colours of the scene you shot, you often find when you try it, that the image IS much better as a black & white image. But apart from that, it’s an analytical tool you can use to enhance the image you created in the camera – by closely examining the shadows, the highlights, and all of the shades of grey in between.
One of the reasons this matters is because so many people are now mesmerised by the colours in their images. And sometimes they cannot “see” what they’ve done – there are bright splashes of colour everywhere, what could possibly be “wrong” with the image. Those “colours” are concealing a deeper truth. The colours themselves are contrasting, aren’t they? The “trouble” is, that they are all the same density – on conversion of the image to explore it further in black & white, it is suddenly appallingly obvious that there is little or no variation in “tonal range”. Without “colour”, the image is as flat as a biscuit.
3 – Atmosphere – one that neither Pascal nor you have mentioned is “atmospheric conditions”. I’ve been fooling around for several years with extreme shots. Perhaps I’m more aware of them, because I live near the coast, and variations in atmospheric conditions seem to be constant – if that makes any sense. Theres a “special time”, just after a heavy shower, when the rain has cleansed the atmosphere, the rain itself has stopped, and the rain was so cold that it has left no noticeable level of water vapour in the air. Suddenly, the air is blazingly clear – and if you’re lucky enough to score a gap in the clouds, the scene in front or your lens will be staggeringly clear. Early morning on a very cold day, and you will get some thing similar. But early morning can also offer you a level of haze that makes the first rays of sunlight seem to be piercing a mist or a fog. Your shot of House Mountain, and the later one under the heading “Elevation”, illustrate this effect.
4 – One thing that’s abundantly plain in all of this, is that we have to concentrate on more than just taking a picture. We have to focus on improving our ability to “see”. The nore we do, the better we “see” and the better our images become – hopefully!
Pete, I do appreciate your comments, and here are some partial replies:
1. One camera and one lens (albeit a zoom): It’s all I can afford, and the zoom is quite good, and so I have considerable flexibility in the field for taking my kind of images. Sometimes I wish I had something wider or longer, but I am mostly content with the quality of what I’ve got. Others will of course have different goals and standards.
2. I looked at a B&W (desaturated) version of the opening image, and found a reasonable range of tones, although the left side of the histogram is more heavily weighted than the middle and right.
3. The House Mountain shot was on a late winter afternoon, and it has greater spikes in the histogram than #2. The elevation one was taken on the same day, and has a much flatter histogram, as befits the hazy scene, I think.
4. Amen brother!